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| CMS-SUS-16-047 ; CERN-EP-2017-130 | ||
| Search for supersymmetry in events with at least one photon, missing transverse momentum, and large transverse event activity in proton-proton collisions at $ \sqrt{s} = $ 13 TeV | ||
| CMS Collaboration | ||
| 19 July 2017 | ||
| JHEP 12 (2017) 142 | ||
| Abstract: A search for physics beyond the standard model in final states with at least one photon, large transverse momentum imbalance, and large total transverse event activity is presented. Such topologies can be produced in gauge-mediated supersymmetry models in which pair-produced gluinos or squarks decay to photons and gravitinos via short-lived neutralinos. The data sample corresponds to an integrated luminosity of 35.9 fb$^{-1}$ of proton-proton collisions at $ \sqrt{s} = $ 13 TeV recorded by the CMS experiment at the LHC in 2016. No significant excess of events above the expected standard model background is observed. The data are interpreted in simplified models of gluino and squark pair production, in which gluinos or squarks decay via neutralinos to photons. Gluino masses of up to 1.50-2.00 TeV and squark masses up to 1.30-1.65 TeV are excluded at 95% confidence level, depending on the neutralino mass and branching fraction. | ||
| Links: e-print arXiv:1707.06193 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; | ||
| Figures & Tables | Summary | Additional Figures | References | CMS Publications |
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Additional information on efficiencies needed for reinterpretation of these results are available here.
Additional technical material for CMS speakers can be found here. |
| Figures | |
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Figure 1:
Representative Feynman-like diagrams for the simulated signal processes: T6gg (top left), T6Wg (top right), T5gg (bottom left), and T5Wg (bottom right). |
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Figure 1-a:
Representative Feynman-like diagram for the simulated T6gg signal process. |
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Figure 1-b:
Representative Feynman-like diagram for the simulated T6Wg signal process. |
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Figure 1-c:
Representative Feynman-like diagram for the simulated T5gg signal process. |
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Figure 1-d:
Representative Feynman-like diagram for the simulated T5Wg signal process. |
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Figure 2:
Validation of the nongenuine ${ {p_{\mathrm {T}}} ^\text {miss}}$ background estimation method with ${\gamma }$+jet and multijet simulations. The direct simulation results are shown as black dots, while the prediction using the jet CR is shown as light blue histogram. The total uncertainty of the prediction is presented as shaded area. The bottom panel shows the ratio of the direct simulation to the prediction. The low- (high-) ${H_\mathrm {T}^{\gamma }}$ selection is shown on the left (right). The number of events corresponds to the expectation in data for an integrated luminosity of 35.9 fb$^{-1}$. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 2-a:
Validation of the nongenuine ${ {p_{\mathrm {T}}} ^\text {miss}}$ background estimation method with ${\gamma }$+jet and multijet simulations. The direct simulation results are shown as black dots, while the prediction using the jet CR is shown as light blue histogram. The total uncertainty of the prediction is presented as shaded area. The bottom panel shows the ratio of the direct simulation to the prediction. The low-${H_\mathrm {T}^{\gamma }}$ selection is shown. The number of events corresponds to the expectation in data for an integrated luminosity of 35.9 fb$^{-1}$. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 2-b:
Validation of the nongenuine ${ {p_{\mathrm {T}}} ^\text {miss}}$ background estimation method with ${\gamma }$+jet and multijet simulations. The direct simulation results are shown as black dots, while the prediction using the jet CR is shown as light blue histogram. The total uncertainty of the prediction is presented as shaded area. The bottom panel shows the ratio of the direct simulation to the prediction. The high-${H_\mathrm {T}^{\gamma }}$ selection is shown. The number of events corresponds to the expectation in data for an integrated luminosity of 35.9 fb$^{-1}$. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 3:
Validation of the background estimation method for electrons misreconstructed as photons using W+jets and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ simulation. The low- (high-) $ {H_\mathrm {T}^{\gamma }} $ selection is shown on the left (right). The number of events corresponds to the expectation in data for an integrated luminosity of 35.9 fb$^{-1}$. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 3-a:
Validation of the background estimation method for electrons misreconstructed as photons using W+jets and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ simulation. The low-$ {H_\mathrm {T}^{\gamma }} $ selection is shown. The number of events corresponds to the expectation in data for an integrated luminosity of 35.9 fb$^{-1}$. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 3-b:
Validation of the background estimation method for electrons misreconstructed as photons using W+jets and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ simulation. The high-$ {H_\mathrm {T}^{\gamma }} $ selection is shown. The number of events corresponds to the expectation in data for an integrated luminosity of 35.9 fb$^{-1}$. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 4:
Validation of the background estimation methods with photons reconstructed in the EE. The expectation for the T5Wg signal scenario with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV and the T6gg signal scenario with a squark mass of 1750 GeV and a neutralino mass of 1650 GeV are shown. The low- (high-) $ {H_\mathrm {T}^{\gamma }} $ selection is shown on the left (right). Below the $ { {p_{\mathrm {T}}} ^\text {miss}} $ distributions, the data divided by the background prediction are shown as black dots, and the relative background components are shown as coloured areas. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 4-a:
Validation of the background estimation methods with photons reconstructed in the EE. The expectation for the T5Wg signal scenario with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV and the T6gg signal scenario with a squark mass of 1750 GeV and a neutralino mass of 1650 GeV are shown. The low- $ {H_\mathrm {T}^{\gamma }} $ selection is shown. Below the $ { {p_{\mathrm {T}}} ^\text {miss}} $ distributions, the data divided by the background prediction are shown as black dots, and the relative background components are shown as coloured areas. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 4-b:
Validation of the background estimation methods with photons reconstructed in the EE. The expectation for the T5Wg signal scenario with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV and the T6gg signal scenario with a squark mass of 1750 GeV and a neutralino mass of 1650 GeV are shown. The high- $ {H_\mathrm {T}^{\gamma }} $ selection is shown. Below the $ { {p_{\mathrm {T}}} ^\text {miss}} $ distributions, the data divided by the background prediction are shown as black dots, and the relative background components are shown as coloured areas. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 5:
Observed data compared to the background prediction. The expectation for the T5Wg signal scenario with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV and the T6gg signal scenario with a squark mass of 1750 GeV and a neutralino mass of 1650 GeV are shown. The low- (high-) $ {H_\mathrm {T}^{\gamma }} $ selection is shown on the left (right). Below the $ { {p_{\mathrm {T}}} ^\text {miss}} $ distributions, the data divided by the background prediction are shown as black dots, and the relative background components are shown as coloured areas. The last three bins in each plot correspond to the search regions. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 5-a:
Observed data compared to the background prediction. The expectation for the T5Wg signal scenario with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV and the T6gg signal scenario with a squark mass of 1750 GeV and a neutralino mass of 1650 GeV are shown. The low- $ {H_\mathrm {T}^{\gamma }} $ selection is shown. Below the $ { {p_{\mathrm {T}}} ^\text {miss}} $ distributions, the data divided by the background prediction are shown as black dots, and the relative background components are shown as coloured areas. The last three bins in each plot correspond to the search regions. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 5-b:
Observed data compared to the background prediction. The expectation for the T5Wg signal scenario with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV and the T6gg signal scenario with a squark mass of 1750 GeV and a neutralino mass of 1650 GeV are shown. The high- $ {H_\mathrm {T}^{\gamma }} $ selection is shown. Below the $ { {p_{\mathrm {T}}} ^\text {miss}} $ distributions, the data divided by the background prediction are shown as black dots, and the relative background components are shown as coloured areas. The last three bins in each plot correspond to the search regions. The rightmost bin includes all events with $ { {p_{\mathrm {T}}} ^\text {miss}} > $ 600 GeV. |
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Figure 6:
Exclusion limits at 95% CL for the T6gg (top left), T6Wg (top right), T5gg (bottom left) and T5Wg (bottom right) models. The solid black curve represents the observed exclusion contour and the uncertainty due to the signal cross section. The red dashed curves represent the expected exclusion contours and the experimental uncertainties. |
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Figure 6-a:
Exclusion limits at 95% CL for the T6gg model. The solid black curve represents the observed exclusion contour and the uncertainty due to the signal cross section. The red dashed curves represent the expected exclusion contours and the experimental uncertainties. |
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Figure 6-b:
Exclusion limits at 95% CL for the T6Wg model. The solid black curve represents the observed exclusion contour and the uncertainty due to the signal cross section. The red dashed curves represent the expected exclusion contours and the experimental uncertainties. |
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Figure 6-c:
Exclusion limits at 95% CL for the T5gg model. The solid black curve represents the observed exclusion contour and the uncertainty due to the signal cross section. The red dashed curves represent the expected exclusion contours and the experimental uncertainties. |
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Figure 6-d:
Exclusion limits at 95% CL for the T5Wg model. The solid black curve represents the observed exclusion contour and the uncertainty due to the signal cross section. The red dashed curves represent the expected exclusion contours and the experimental uncertainties. |
| Tables | |
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Table 1:
Observed data compared to the background prediction and the expected signal yields for two signal scenarios. The expectations are given for the T5Wg signal scenario with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV and the T6gg signal scenario with a squark mass of 1750 GeV and a neutralino mass of 1650 GeV. The quadratic sum of statistical and systematical uncertainties is given. Only experimental uncertainties for the signal model are stated. |
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Table 2:
Systematic uncertainties for background determined from control samples in data (first two rows) and simulation (all other rows). If two values are given, the first one is for simulated SM backgrounds, while the latter is for simulated signal. The PDF and scale uncertainties for the signal simulation affect the shape only, as the uncertainty in the rate is already considered in the overall cross section uncertainty [35]. |
| Summary |
| A search for physics beyond the standard model (SM) in final states with at least one photon, large missing transverse momentum, and large total transverse event activity has been presented using data corresponding to an integrated luminosity of 35.9 fb$^{-1}$ of proton-proton collisions at $ \sqrt{s} = $ 13 TeV recorded by the CMS experiment at the LHC in 2016. The SM background is estimated from data and simulation, and is validated in several control regions. No significant signs of new physics beyond the SM are found, and the data are interpreted in simplified models motivated by gauge-mediated supersymmetry breaking. Gluino masses up to 1.50-2.00 TeV and squark masses up to 1.30-1.65 TeV are excluded at 95% confidence level, depending on the neutralino mass and mixture. |
| Additional Figures | |
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Additional Figure 1:
Covariance between the search regions. |
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Additional Figure 2:
Correlation between the search regions. |
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Additional Figure 3:
Observed significance for T6gg model. |
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Additional Figure 4:
Observed significance for T6Wg model. |
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Additional Figure 5:
Observed significance for T5gg model. |
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Additional Figure 6:
Observed significance for T5Wg model. |
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Additional Figure 7:
Signal yield after several analysis cuts for the T6Wg model with a gluino mass of 1600 GeV and a gaugino mass of 100 GeV. The number of events which would have been produced in the collisions is given in the first bin. The second bin contains events, in which a reconstructed photon with the criteria defined in the analysis is reconstructed. The third bin contains events which have $ {EM {H_{\mathrm {T}}} } > $ 700 GeV in addition to a photon. In nearly all events of this model, ${EM {H_{\mathrm {T}}} }$ exceeds 700 GeV. The fourth bin contains events with a reconstructed photon, $ {EM {H_{\mathrm {T}}} } > $ 700 GeV, and $|\Delta \phi (\pm { {p_{\mathrm {T}}} ^\text {miss}}, {p_{\mathrm {T}}} ^{\gamma })|> $ 0.3. The last six bins are the event yields in the search regions. |
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Additional Figure 8:
Observed and expected exclusion contours for SUS-16-047 (this analysis) and SUS-16-046 for the T6gg model. |
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Additional Figure 9:
Observed and expected exclusion contours for SUS-16-047 (this analysis) and SUS-16-046 for the T6Wg model. |
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Additional Figure 10:
Observed and expected exclusion contours for SUS-16-047 (this analysis), SUS-16-046, and SUS-16-023 for the T5gg model. |
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Additional Figure 11:
Observed and expected exclusion contours for SUS-16-047 (this analysis) and SUS-16-046 for the T5Wg model. |
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Compact Muon Solenoid LHC, CERN |
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